7yo girl sexually assaulted and rescuer stabbed

A YOUNG girl has been sexually assaulted and a man who tried to help her was stabbed in a horrific incident in Sydney's southwest overnight.

Police swooped on the suburb of Kogarah about 7.55pm along with other emergency services who were called to the St George Dance Centre on Derby St, after reports of a concern for welfare and a stabbing.

According to NSW Police, a seven-year-old girl was assaulted and sexually assaulted in a toilet by a 54-year-old man.

When a 46-year-old man confronted the alleged offender and a struggle began, he was stabbed in the abdomen, and neck.

This morning, a NSW Police spokesman told news.com.au that the alleged attacker, the stab victim and the young girl were not known to each other.

Superintendent Julian Griffiths said the accused man had no links to the dance studio.

"It appears to be a random, isolated incident," he said.

"(He) will not be in a position to assist police inquiries until early next week or when we receive medical advice to confirm he's available to be spoken to."

He also praised the actions of the Good Samaritan who intervened.

"He was aware that the child could not be accounted for and was assisting others in locating her," he said.

He added the girl's safety and welfare is "paramount in this investigation".

Witnesses came to the injured man's aid and detained the offender until the arrival of authorities.

The older man was arrested and taken to St George Hospital in a stable condition suffering facial swelling and bruising. He remains under police guard.

The 46-year-old man was taken to St George Hospital in a stable condition for treatment to his stab wounds.

ACTiv Elite Performers - a performing arts studio for singers, dancers and actors of all ages and abilities which is based at the same studio - posted a message of support for the venue this morning.

"Our hearts go out to our friends at St George Dance Centre after hearing the news of this senseless and violent attack in our community," they wrote on Facebook. "Lots of love to the families, staff and children affected and to the brave man who intervened."

Mo Hariri was celebrating his 24th birthday with his friends in the courtyard area of his family's chicken shop and told the Daily Telegraph he heard angry noises coming from the St George Dance Studio across the road.

"We thought someone was having a heart attack or something but then this bloke runs out screaming: 'call the police," Mr Hariri said.

"He looked so scared like he was having a panic attack."

Supt Griffiths told reporters a strikeforce had been set up to investigate the "concerning" matter.

"I think an incident like this will have everyone considering their own personal safety measures," he said.

"We would be encouraging people to continue to show vigilance in public areas or shared facilities."

A police spokesman told news.com.au the alleged attacker is yet to be released from hospital.

"A crime scene was established by St George Police Area Command officers and investigations are continuing," a NSW Police spokesman said this morning.

"The 54-year-old is expected to be released from hospital some time this morning, at which time he will be taken to Kogarah Police Station to assist with inquiries."